Seamless Steel Pipe for Marine Purpose

Marine seamless steel pipe is very common in marine engineering. Two systems of ship and marine engineering generally need three kinds of steel pipes covering steel pipe with the conventional system, construction steel pipe and special steel pipe. This steel tube is applicable to Class I and Class II pressure tubing, boiler and superheater that are used for manufacturing ships.

Certificates

• In 1998, our marine seamless steel pipes were certified by China CCS classification society factory.
• In 1999, JST marine steel tubes passed British LR classification society factory certification.
• In 2001, this product gained Norway DNV classification society factory certification.
• In 2003, JST marine seamless steel pipes received USA ABS classification society factory certification.
• In 2004, our products are certified Japan NK classification society factory.
• In 2005, our marine steel tubes obtained France BV classification society factory certification.
• In 2007, this product passed Germany GL classification society factory certification.

Specifications of Marine Seamless Steel Pipe Table 1 Grade of Seamless Steel Pipe (Pressure Tubing)

Pipe Range	I		Ⅱ		Ⅲ
	Designed Pressure(Mpa)	Designed Temperature (℃)	Designed Pressure (Mpa)	Designed Temperature (℃)	Designed Pressure (Mpa)	Designed Temperature (℃)
	>				≤
Steam and Hot Oil	1.6	300	0.7-1.6	170-300	0.7	170
Fuel Oil	1.6	150	0.7-1.6	60-150	0.7	60
Other Media	4.0	300	1.6-7.0	200-300	1.6	200

Note:

• When the designed pressure and temperature reach the ones in the above Class I, this steel pipe belongs to Class I pipe. If it meets the pressure and temperature of Class II, it is defined to be the Class II pipe.
• Other media refer to air, water, lubricating oil and hydraulic oil.
• Class III seamless steel tubes can be manufactured in accordance with the national standards approved by the ship inspection department.
• 1) As for the seamless steel pipe for boiler and super heater purpose, the working temperature of wall thickness does not exceed 450℃.
• 2) The dimension of marine seamless steel pipe should firstly select the general steel pipe size in the first group of GB/T7395-1998 table one. The outside diameter of steel tube should choose the standard outside diameter size in the first series of GB/T7395-1998. We can also produce pipes with other specifications not appear in the GB/T7395-1998 table one.

Table 2 Allowable Deviation of Outside Diameter and Wall Thickness

Type	Size (mm)		Allowable Deviation
Hot-Rolled Pipe	Outside Diameter	≤ 159	± 1.0%, Min. ± 0.5 mm
		> 159	± 1.25%
	Wall Thickness	≤ 20	+ 15%        + 0.45 mm
			-10%, Min. -0.30 mm
		> 20	± 10%
		D≥ 351 Hot Expanded Pipe	± 15%
Cold-Drawn Pipe	Outside Diameter (D)	≤ 30	± 0.2 mm
		30 < D ≤ 50 < DIV>	± 0.30 mm
		> 50	± 0.8%
		1.5 ≤ S ≤3.0	+ 12.5%   + 10%
		> 3.0	± 10%

Note:

• The tortuosity of marine seamless steel pipe should not exceed the following value”
• 1) When nominal wall thickness is equal to or less than 15 mm, the turtuosity should not be more than 1.5 mm/m.
• 2) When nominal wall thickness is more than 15 mm, the turtuosity should not exceed 2.0 mm/m.
• 3) For the hot expanded pipe with the outside diameter of not less than 351 mm, it should not be over 3.0 mm/m.
• If the roundness and wall thickness are not uniform in the same cross section of steel tubes, they should not exceed eighty percent of outside tolerance and wall thickness tolerance respectively. These should be marked out in the contract according to clients' requirements.

Table 3 Grade and Chemical Composition of Marine Seamless Steel Pipe

Type	Grade	Deoxidation Method	Chemical Composition (Mass Fraction) (％)
			C	Si	Mn	S	P	Residual Elements
								Cr	M0	Ni	Cu	Total
			≤			≤		≤
Carbon Steel and Carbon Manganese Steel	320	Killed or Balanced	0.16	0.35	0.40-0.70	0.035	0.035	0.25	0.1	0.3	0.3	0.7
	360		0.17	0.35	0.40-0.80
	410		0.21	0.35	0.40-1.20
	460		0.22	0.35	0.80-1.40
	490		0.23	0.35	0.80-1.50

Note: Grade 490 is only applicable to pressure tubing.

Table 4 Room Temperature Mechanical Properties of Steel Tube

Grade	Tensile Strength (MPa)	Yield Point (MPa)	Elongation (％)
		≥
320	320-440	195	25
360	360-480	215	24
410	410-530	235	22
460	460-580	265	21
490	490-610	285	2l

Note: Marine seamless steel pipe is often delivered in normalizing state or normalizing and tempering state. If it is delivered in hot-rolled state, the final rolling temperature should not be below Ar3.

Table 5 High Temperature Mechanical Properties of Steel Tube

Grade	High Temperature Yield Point (MPa )
	Temperature (°C)
	50	100	150	200	250	300	350	400	450
320	172	168	158	147	125	100	9l	88	87
360	192	187	176	165	145	122	111	109	107
410	217	210	199	188	170	149	137	134	132
460	241	234	223	212	195	177	162	159	156
490	256	249	237	226	210	193	177	174	171

Founded in 1984, Jiangyin Changjiang Steel Tube Making Factory is a professional manufacturer of marine seamless steel pipes in China. Our products also mainly cover casing, tubing, line pipe, drill pipe, high pressure boiler pipe, cylinder tube, hydraulic prop tube, fluid pipe, structure pipe, etc. They have passed API 5CT, API 5L, API 5DP, CCS, LR, DNV, ABS, NK, BV, GL, PED, SGS, ISO9001:2000 and ISO14001:2004 certifications. Our steel tubes have won widespread praise and recognition by customers.